1. Field of the Invention
The invention relates to a network comprising a plurality of network equipment units interconnected via a ring which conveys transport frames of data units at a rate that determines the capacity of the ring, the capacity being formed by a used part and an unused part.
The invention likewise relates to a network equipment unit intended to be interconnected with at least another network equipment unit via a packet switching ring which conveys transport frames whose rate determines the capacity of the ring, said capacity being formed by a used part and an unused part.
The invention finally relates to a method of controlling the access to an interconnection ring of a plurality of network equipment units, said ring forwarding transport frames of data units at a rate that determines the capacity of the ring, said capacity being formed by a used part and an unused part.
The invention has meaningful applications, more specifically in the field of local area networks, and more particularly in the field of combining rings using an ATM (Asynchronous Transfer Mode) protocol, for, for example, wideband ISDN networks.
2. Description of the Related Art
One of the problems posed in this type of networks is that of sharing the capacity of the ring between the various networks equipment units. The token ring technique, which is notably described in chapter 3.4.3 of the publication entitled "Reseaux, Architectures, Protocoles, Applications" by Andrew Tanenbaum, published by InterEditions in 1990, forms the conventional solution to this problem for rings of the Token Ring, FDDI . . . type. It consists of causing a particular bit sequence called a token to be forwarded permanently between the network equipment units when they have nothing to transmit. When an equipment unit wishes to transmit a frame, it is to take possession of the token and replace this token on the ring by the frame it wishes to transmit. A single equipment unit can thus transmit at a given instant, which induces all the others to postpone their request.